System variables substitution in parameter library members

With symbolic substitution, you can reduce the number of parameter libraries that you maintain. When the member is read, the value of the symbol is substituted for the symbol. The symbol must begin with an ampersand followed by one to eight characters and, optionally, a period. You can define your own symbols by placing them in the IBM PARMLIB member IEASYMxx.

Symbolic substitution example

Symbolic names can be concatenated with a string, at the beginning, middle, or end of the string, as shown in the following example:

In the example, if &SYSPLEX=BMC1 and &SYSNAME=SJSD, the string would convert to the following statement:

For more information about symbolic substitution, refer to the discussion of system symbols and symbolic substitution in the IBM Initialization and Tuning Reference.

Controlling symbolic substitution

You can control symbolic substitution on a member-by-member basis by adding a PROCESS statement control card to the beginning of each member.

The statement uses the following syntax:

If present, the PROCESS statement must be the first statement in the member and must begin in column 1. The keywords must be separated by a comma. An example follows:

• SYM indicates whether symbolic substitution is allowed:

  • YES (the default) indicates that symbols are to be replaced by their value, if the calling program has enabled symbol substitution.
  • NO indicates that symbolic substitution should be suppressed for this member, even if the calling program has enabled substitution.

  Substitution will not be performed on comments or anything beyond column 71.

• LIST indicates whether the contents of the member being processed should be written to the job log (displayed as WTO messages), one statement at a time as the member is read:
  • YES causes the entire contents of the member, except the PROCESS statement, to be written to the job log.
  • NO (the default) indicates that the contents of the member should not be written to the job log.

If substitution is performed, two WTO messages are displayed for each statement on which substitution was performed. The first message contains the statement with the symbol, and the second message contains the same statement with the substituted value of the symbol. The second statement is also prefixed with <> to indicate that the statement was modified.